The subject matter disclosed herein relates generally to the field of elevators, and more particularly to elevator power systems.
An elevator system, such as traction, hydraulic, and self-propelled elevator systems, based on the application (e.g., high rise buildings) can utilize a power system to propel a car within an elevator shaft. At present, the power system can employ a power electronics inverter (e.g., as variable speed alternating drive (AC) motor drive) to improve performance of the power system. However, switching of power electronics devices in power system includes inherent electromagnetic interference (EMI) problems.
In general, EMI noise can be divided into two major groups: differential mode (DM) noise and common-mode (CM) noise. DM noises are conducted between phases. CM noises are conducted together with all phases through the parasitic capacitors to the ground. CM noises are with serious concern for motor drives because CM noises increase the EMI in the motor drive and damage the motor bearing and winding insulation. Unfortunately, in certain applications, solutions such as adding CM filters to attenuate CM noises are not viable due to the significant weight penalty of each CM filter.